There's no fixed minimum number of cubes you need, and a quick look at the leaderboard will show that people do make it past wave 4000 with as little as about 500k time cubes, but I'd recommend having at least a million or if you want an easier time at least 1.5 million.

While having more cubes seems like it should make things easier, upgrades have rapidly diminishing returns on investment. Every single level of every type of upgrade costs more than the previous level and is less of a gain than the previous level was. Instead of relying on more cubes and upgrades to boost your damage, you will be relying mainly on dimension shifts to boost your damage. Dimension shift will give you a fixed % increase (at least 5% but can be upgraded to more) every use, and while it takes hours to recharge, it can recharge even when the game isn't running. Although dimension shift's damage boost isn't permanent, it'll last until you do your next time warp, and running the game and hitting the button every few hours is far less work and will build your damage up much faster than trying to grind through areas you can beat repeatedly.

For this run, starting improvements are a waste. Instead of doing many shorter runs like you've most likely been doing up until now, this is a single very deep run. It will go on for a quite a while and the amount of time you would save at the begining will be negligable compared to the total amount of time you'll spend in the run, and will likely be counter productive as what you could have bought instead will help you more. You'll need to put starting wave to level 1 (starting wave 11) to unlock the right side of the tree, but don't buy any more starting wave upgrades than that, and don't buy any starting gold upgrades.

Max the boss timer upgrade as you'll need all the time you can get there, and max the upgrade above it so you only need to fight 5 enemies per wave.

Sell all your time cube chance and increase time cube amount upgrades. This is a guide on getting to wave 4000, not farming cubes, and not only will those upgrades use cubes better spent elsewhere, but they will actively hurt your ability to progress. More on this later.

Once you hit a certain point, you will only make progress when all of your skills are active, and only your click weapons will be doing significant damage. Therefore, you should consider the ability upgrades to effectively be continous upgrades.

Upgrade dimension shift at the top of the tree to at least 3/5 (8%). Feel free to add another level to make that 9% if you have enough spare cubes, but that next upgrade is pricy, so the cubes might be better spent elsewhere if you're trying to scrape by with a very low cube count, however dimension shift will be your primary method of boosting your damage so don't skimp here.

You'll want to max most of the ability improvements here, 10 shot spread shot, critical strike chance 2.0x, critical strike multi 10x, explosive shots 8x, team dps 6x, as these will always be active while you're making progress and they add a lot of damage for not that many cubes. Automatic fire is too expensive to max, but try for level 6 at least as the click pistol will be your main damage dealer, so it will have a massive impact on your damage.

Duration and cooldown improvements are more of a convienience than needed but you may want to invest some to help you along if you have spare cubes after the vitals.

This tree is very good for getting some extra multipliers to stack on top of your damage.

The top of the tree gives you a cheap 2x on everything.

Get all the "click <color> block does #x damage" up to at least 6x.

Since the click weapons on auto mode will always be tagetting blocks targetted by team members, and when you aim weapons manually you should be aiming for blocks targetted by team members, the "clicking a block targetted by" upgrades are almost as good as permanent multis, so get them all up to at least 6x.

The bottom of the tree should also be boosted quite a bit for a bigger boost on team member targets.

If you want, feel free to max the critical strike upgrades here as well.

As mentioned in the progress tree section, don't upgrade starting gold, it's a waste here. Rainbow ball isn't very useful as it gives you only a couple minutes worth of gold and you'll commonly be building hours of gold from not playing the game. Block conversion isn't going to do much for you either.

Rainbow enemy chance is a semi-helpful upgrade as rainbow enemy waves are much easier to defeat and could mean the difference between having enough ability time to power through an extra boss or not at some times, but is more of a convinence than needed and if you're tight on cubes they'd be better spent elsewhere.

Boost all of the block gold multipliers and the gold % quite a bit.

This is where you're going to dump the rest of your time cubes.

Start out with the individual effects on the left side, spread rifle never misses, particle ball 2x, flak never misses, rocket hits diagonally.

Then, distribute the rest of your time cubes amount team member dps multis and the all team multi. I've read that it's better to have the level of the team dps multi a bit higher than you have the levels of the individual members, but I havn't done the math myself.

Sell all your weapon cube drop upgrades, the cubes are better spent elsewhere, and having weapon drop cubes on the field makes taking down bosses much harder.

The most important upgrades surprisingly are probably the targetting speed upgrades. The automatic fire upgrades are almost negligable compared to the faster rate of fire you'll have when the auto-fire ability is active. The gold spawn upgrades will be fairly useless. Reducing the clicks/rocket is useful but gets prohibitably expensive very quickly. Increasing rocket spread can also be useful, however as those extra rockets will usually be hitting bocks not targetted by team members, they will be doing much less damage as they'll be missing some multipliers. A few rocket speed upgrades are a good idea as it'll increase the percent of rockets that actually hit something. The targetting speed upgrades will get the weapons hitting their intended targets as fast as possible, which is good not only to prevent them from shooting out into nothing as they cross gaps, but also since their targets are also targetted by team members, which will add on extra multipliers.

If you have the extra weapon cubes after getting those upgrades, get the click cannon, but don't compromise on click pistol targetting speed to get it.

You should know what to do by now up until you slow to a crawl. Then switch to the following play style:

1. Run the game.
2. Activate all abilities at the same time
3. Use cooldown reduce
4. Activate all abilities at the same time.
5. Once abilities all ended, close the game.
6. Wait at least the amount of time until cooldown reset has recharged.
7. Go to step 1.

Things will get progressivly slower and slower until you get into a spec ops section. As soon as you get your first team member out of training to a spec ops you'll always get a massive speed boost. Always prioritize trying to upgrade a team to the next upgrade, don't just spread out level increases. Always activate dimension shift whenever you get the oppertunity. Even if you hit a point where you can't beat a boss at all, using a full activity set, then starting another, another dimension shift or 2 (or maybe more if you're really stuck) will always get you moving again, so keep dimension shifting. Even if you don't intend to do a run of the cycle still run the game just to dimension shift from time to time, it only takes like 30 seconds to run the game hit dimension shift and close it.

Closing the game actually is an important part of the cycle. Your team's damage will be so insignificant that they won't be destroying any blocks at all over short periods of time, so if you leave the game open and end up on a boss wave, you might not destoy any blocks during the boss timer, and your income will be 0. With the game closed you'll still be earning gold.

Never give up when on a training x.4 section. Things can seem hopeless during the last few boss waves, but once you break through getting a single team member into spec ops you'll gain a massive boost and things will go smoothly again for quite a while.

Bosses that contain time or weapon cube drops will pose a significantly greater challenge than normal boss fights. Cube drops have massive hp and WILL cause you to lose waves you would have beaten otherwise. You will often have to manually intervene on these waves, taking manual control of weapons when they make bad targetting decisions.

Normally you can just leave everything on auto targetting, and you should start bosses like this. If one of your click weapons(especially the click pistol) targets a cube drop before the end of the wave, you may have a problem, and need to take control of that weapon.

The key to defeating cube drops is the "clicking a block targeted by <weapon> does #x" powerups. When the cube drops are the last remaining cubes on the field, multiple team members will be targetting the cube drop at the same time, so those multipliers will stack, giving your click weapons the massive damage needed to cut them down. If your click weapons target cube drops earlier than that, their damage will likely be negligable compared to the cube drop's hp and their damage will be wasted. When you see a click weapon target one of these drops, you need to take manual control of it, and target blocks targetted by other team members until only cube drop blocks are left, and only then switch back to targetting them.

Well that's about it. While these tips will help you get there faster, any build will get you there eventually with enough dimension shifts. Things will get very slow at times, but this is really just a test of patience, so if you stick it out, you will win. Good luck.